Bash: How to use getops correctly to parse the data in the arguments?

Question

I need to create a script.

The script must accept the following command line options: -n account name, and -r number of accounts. Upon execution the script must create a batch of user accounts based on the account name and number of accounts.

For example: /usr/local/bin/batch_user -n bob -r 5 should create the user accounts bob1, bob2, bob3, bob4, bob5

This is the first time I use getopts and I'm having some problems understanding how to use it, here's what I wrote so far:

#!/bin/bash
usage () { $0 -n usernanme -r number of creations };
while getopts ":n:r:" arg; do
case "${arg}" in
n)
n=${OPTARG}
;;
r)
r=${OPTARG}
;;
esac
done

First, I'm not sure how to parse the data after the first option (-n) then how do I run on the number (-r) to create the users? Thanks in advance

Answer 1

You can use:

#!/bin/bash

usage () { echo "$0 -n usernanme -r number of creations"; }

while getopts ":n:r:" arg; do
   case "${arg}" in
      n) n=${OPTARG} ;;
      r) r=${OPTARG} ;;
   esac
done

for ((i=0; i<r; i++)); do
   echo "Adding user: ${n}${i}"
done